1. Field of the Invention
The present invention relates to an ion implantation apparatus and a control method for an ion implantation apparatus.
2. Description of the Related Art
In a semiconductor production process, a process of implanting ions into a semiconductor wafer (hereinafter, it may be referred to as an “ion implantation process”) is generally performed for the purpose of changing the conductivity and/or the crystalline structure of the semiconductor and the like. An apparatus that is used in the ion implantation process is called an ion implantation apparatus and has a function of forming an ion beam by generating ions using an ion source and accelerating the generated ions and a function of transporting the ion beam to a vacuum processing chamber and irradiating a wafer with the ion beam inside the vacuum processing chamber. In addition, in the ion implantation apparatus, a device that supplies a wafer before the implantation of ions to the vacuum processing chamber and takes out the wafer to which the ions have been implanted (hereinafter, it may be referred to as a “wafer conveyance device”) is disposed.
The wafer conveyance device includes a load lock chamber used for bringing a wafer placed under the atmospheric pressure into the vacuum processing chamber. After bringing a wafer into the load lock chamber under the atmospheric pressure, the wafer conveyance device evacuates the load lock chamber, causes the load lock chamber that is in the vacuum state and the vacuum processing chamber to communicate with each other, and brings the wafer into the vacuum processing chamber. Since a time required for bringing the wafer into is highly influenced by an evacuation time of the load lock chamber, the processing capability of wafer conveyance can be increased by arranging a plurality of load lock chambers. For example, as a wafer conveyance device of which the conveyance capability is increased, a configuration may be employed in which two load lock chambers are arranged and an intermediate conveyance chamber is arranged between the load lock chambers and the vacuum processing chamber. In the intermediate conveyance chamber, a conveyance mechanism used for performing wafer conveyance between the vacuum processing chamber and the load lock chambers is disposed.
Since the intermediate conveyance chamber is arranged to be adjacent to the vacuum processing chamber, there are cases where the intermediate conveyance chamber is contaminated due to inflows of ions included in an ion beam transported to the vacuum processing chamber, particles sputtered by the ion beam, and the like. When the intermediate conveyance chamber and/or the conveyance mechanism disposed in the intermediate conveyance chamber is contaminated, there is a concern that a wafer that is in the middle of the conveyance process is influenced by the contamination.